Distribution unit for pitless wells

ABSTRACT

A DISTRIBUTION UNIT FOR USE WITHIN A WELL CASING OF A PITLESS WELL INSTALLATION SERVES TO ESTABLISH A PRESSURE ISOLATED CHAMBER INTERCOMMUNICATING THE DROP PIPE OF THE WELL WITH A LATERAL DISCHARGE OUTLET. THE UNIT INCLUDES A PAIR OF END SUPPORTS HELD IN SPACED RELATION BY A PERFORATED CONDUIT, EACH SUPPORT CARRYING A PACKER ENGAGEABLE IN SEALING RELATION WITH THE WELL CASING. ONE END SUPPORT IS ENGAGEABLE WITH A HANGER PIPE FOR SUSPENDING THE UNIT AT THE LEVEL OF THE DISCHARGE OUTLET, AND THE OTHER END SUPPORT IS ENGAGEABLE WITH THE DROP PIPE FOR INTRODUCING FLUID THROUGH THE CONDUIT PERFORATIONS INTO THE CHAMBER DEFINED BETWEEN THE PACKERS. EACH PACKER INCLUDES A FLEXIBLE RESILIENT SLEEVE EXPANDABLE INTO SEALING ENGAGEMENT AGAINST THE CASING WALL WHEN THE CHAMBER IS SUBJECTED TO PRESSURE, TOGETHER WITH AN OUTER RIB STRUCTURE PROVIDING A SEAL WHEN THE CHAMBER IS SUBJECTED TO VACUUM.

Sept. 20, 1971 E. A. cox EIAL 3,605,686

DISTRIBUTION UNIT FOR PI'ILESS WELLS Filed Aug. 29. 1969 INVENTORSI EDWARD A. COX CONRAD R MEDINA ATTORNEYS United States Patent ice 3,605,886 DISTRIBUTION UNIT FOR PITLESS WELLS Edward A. Cox, Lake Zurich, and Conrad R. Medina,

Des Plaines, 11]., assignors t0 Clayton Mark and Company, Evanston, Ill.

Filed Aug. 29, 1969, Ser. No. 854,243 Int. Cl. F21b 23/00, 33/03 US. Cl. 166-89 Claims ABSTRACT OF THE DISCLOSURE A distribution unit for use within a well casing of a pitless well installation serves to establish a pressure isolated chamber intercommunicating the drop pipe of the well with a lateral discharge outlet. The unit includes a pair of end supports held in spaced relation by a perforated conduit, each support carrying a packer engageable in sealing relation with the well casing. One end support is engageable with a hanger pipe for suspending the unit at the level of the discharge outlet, and the other end support is engageable with the drop pipe for introducing fluid through the conduit perforations into the chamber defined between the packers. Each packer includes a flexible resilient sleeve expandable into sealing engagement against the casing wall when the chamber is subjected to pressure, together with an outer rib structure providing a seal when the chamber is subjected to vacuum.

The present invention relates to well distribution apparatus and more particularly to an improved distribution unit for interconnecting the drop pipe and the lateral discharge outlet in a pitless well installation.

A typical pitless well installation may include a well casing or pipe extending from grade level into the ground to a water bearing region. In a deep well system a submersible pump unit is located near the bottom of the well casing and operates to force pressurized fluid upwardly through a drop pip'e within the casing to a lateral discharge opening in the casing wall below frost level, from which the fluid is conducted to the point of use. Pressurized fluid from the drop pipe travels to the lateral discharge opening through a distribution unit suspended in the well casing from a hanger pipe extending to the top of the well casing where it is attached to a well cap or the like.

Many types of pitless distribution units are known. Many of these are subject to the disadvantage that they require a special fitting or the like at the lateral discharge outlet for receiving the distribution unit. Another type, which does not require a special fitting, includes packers such as O-ring seals, leather cups or the like for sealing against the inner wall of the well casing to provide an isolated chamber through which the drop pipe commu nicates with the lateral discharge opening. Known units of the latter type have been subject to many disadvantages including weight, complexity, expense and unreliability. Further, known units have been difficult to install and difficult to remove from the well casing after a period of time for repair, replacement or the like.

In some types of shallow wells wherein the pump is located above grade, it is desirable to use a distribution unit which seals against vacuum as well as pressure. Many units used in the past although effective to provide a seal against pressure have not been able to provide an effective seal against a vacuum or suction condition.

Among the important objects of the present invention are to provide an improved distribution unit for use in pitless well installations; to provide a unit which seals against both pressure and vacuum; to provide a unit which is light in weight and extremely simple and convenient Patented Sept. 20, 1971 to use; and to provide an improved packer construction for a distribution unit capable of sealing against both pressure and vacuum.

In brief, a pitless distribution unit constructed in accordance with the present invention for use within a well casing may include a supporting structure comprising a pair of end supports held in spaced apart relation by means of a conduit extending between the end supports and including a plurality of perforations. The upper end support includes means for attachment to a hanger pipe for suspending the distribution unit in a well casing, while the lower end support includes means engageable with a drop pipe for channeling fluid from the drop pipe by way of the perforated conduit into the region between the end supports. In order to provide an isolated, sealed chamber communicating with a lateral discharge opening extending from the well casing, each support is provided with a novel packer capable of sealing both against pressure and vacuum. Each packer includes a sleeve telescoped within the well casing having an outer surface engageable with the wall of the well casing and an inner surface exposed to fluid pressure fluctuations within the chamber. The sleeve has an initial interference fit with the well casing to provide an initial seal against both pressure and vacuum. In addition, the sleeve is formed of flexible, resilient material and under increasing pressure can expand into tighter sealing relation against the well casing. A novel rib construction produces a seal in response to a suction condition within the chamber, and includes a relatively thick and inflexible rib together with an adjacent thin and relatively flexible rib which in response to vacuurn is wedged into sealing relation between the relatively thick inflexible rib and the wall of the well casing. The rib construction also increases the effectiveness of the seal under pressure conditions and simplifies installation and removal of the unit.

The invention together with the above and other objects and advantages may be better understood with reference to the following detailed description of an embodiment of the invention illustrated in the accompanying drawing wherein:

FIG. 1 is a sectional view of a distribution unit constructed in accordance with the present invention illustrated in place in a pitless well installation;

FIG. 2 is a top view of the upper end support of the unit of FIG. 1;

FIG. 3 is a fragmentary sectional view on an enlarged scale of a portion of one of the packers of the unit of FIG. 1 illustrated in its relaxed condition prior to insertion within the well casing; and

FIG. 4 is a view similar to FIG. 3 illustrating the packer inserted in the well casing and subjected to a suction condition.

Having reference now to the drawing, there is illustrated a pitless distribution unit designated generally by the reference numeral 10 and constructed in accordance with the principles of the present invention. The unit 10 is installed in a pitless well including a well casing 12 having a lateral discharge outlet 14 provided with a coupling 16 for connection to a suitable fluid delivery pipe. In a typical installation, the outlet 14 is located below grade and below frost level so that freezing problems are avoided. Fluid is supplied to the unit 10 and the outlet 14 through a drop pipe 18 extending downwardly from the unit 10 within the well casing 12. The unit 10 together with the drop pipe 18 is suspended within the well casing by means of a hanger pipe 20 extending upwardly within the well casing from the unit 10 and attached to the top of the well installation, as for example to a well cap or the like.

In a typical deep well installation the drop pipe 18 is connected to and supports a submersible pump unit located 3 within the well casing and submerged in water. The submersible pump unit forces pressurized fluid upwardly through the drop pipe 18 to the point of use. In a shallow well installation the pump may be located above grade and operate to draw water up through the drop pipe 18 by creating a suction condition.

In general, the unit serves to channel fluid supplied through the drop pipe 18 to the lateral discharge outlet 14. In accordance with important features of the present invention, the unit 10 is not only simple in construction, light in weight and easy to use, but is also capable of providing an initial seal and a pressure energized seal against both pressure and vacuum conditions.

More specifically, the unit 10 includes an upper end support 22 and a lower end support 24 maintained in spaced relation by means of a conduit 26 attached at its ends to the support. Each of the supports 22 and 24 is provided with an improved packer 28 described in greater detail below and engageable in sealing relation with the well casing 12 to define between the packers 28 a chamber 30 isolated from the remainder of the well casing. The chamber 30 serves as part of the path of the fluid flowing through the well installation from the drop pipe 18 to the lateral discharge outlet 14.

Conveniently, the end supports 22 and 24 are in most respects identical in construction. Each support serves both to support the corresponding packer 28 and to establish a connection With the drop pipe 18 and the hanger pipe respectively. More specifically, each support includes a plate section 32 provided with recesses 24 enabling the plate section 32 to be securely and firmly encapsulated within the body of the corresponding packer 28. The end supports 22 and 24 further each include a hub 36 extending both inwardly and outwardly of the plate section 32. The inwardly extending section is internally threaded to receive one end of the conduit 26. With reference to the upper end support 22, the outwardly extending portion of the hub 36 is provided with internal threads for attachment to the hanger pipe 20 whereby the unit 10 and the drop pipe 18 may be supported from the hanger pipe 20. In order to isolate the conduit 26 and thus the chamber from the hanger pipe 20 and the portion of the well casing above the unit 10, the hub portion 36 is divided by a wall 38 lying in the plane of the plate section 32. It will be understood by those skilled in the art that hanger means other than the hanger pipe 20 may be used for suspending the unit 10 from the top of the well installation and the upper end support 22 may be designed accordingly.

As noted above, the lower end support 24 is substantially similar to the support 22. The hub portion 36 of the lower end support 24 is threadedly connected to the lower end of the conduit 26 and to the upper end of the drop pipe 18. Fluid rising through the drop pipe 18 communicates through a passageway 40 in the hub portion 36 with the interior of the conduit 26.

In order to admit fluid from the conduit 26 to the chamber 30 defined between the packers '28, the conduit is provided with opening means in the form of a large number of relatively small perforations 42. The use of several relatively small perforations rather than one or a small number of large openings provides an extremely low head loss as water passes through the unit 10 while serving to decrease the effect of pressure surges caused by start up of the pump or the like.

As indicated above, the unit 10 may be used in a deep well installation wherein a submersible pump unit is attached to the lower end of the drop pipe 18. Such a unit customarily includes an electrically operated drive motor together with a fluid pump. In order to permit connection of electrical cables from the top of the Well to the submersible pump unit, there is provided a cable conduit 44 extending through recesses 46 in the hub portions 36 of both the upper end support 22 and the lower end support 24. The cable conduit is held in place by means of spring grip washers 48, and the seal between the chamber 30 and the remainder of the interior of the well casing 12 is maintained by means of a pair of O-ring seals 50 mounted in grooves in the Walls of the recesses 46.

In accordance with an important aspect of the present invention, the packers 28 of the unit 10 are capable of sealing off the chamber 30 from the remainder of the well casing both during pressure and vacuum conditions. In addition, the packers 28 allow easy insertion of the unit 10 and associated drop pipe and pump unit into the well casing while providing both an initial seal and an additional pressure energized seal against both pressure and vacuum.

More specifically, each of the packers 28 is formed of flexible resilient material, such as nitrile rubber having a durometer hardness of about 50 to 60, or other elastomeric material. Each packer 28 includes a body portion 52 serving to support the packer 28 on the respective end supports 22 and 24. Conveniently, the packers and end supports are fabricated as a unitary conveniently handled and simple unit. In the illustrated arrangement, the plate sections 32 of the end supports are encapsulated within the body portions 52 of the packers 28, and the recesses 34 are filled with the material of the packers 28 durin the encapsulating operation, thereby firmly to hold the packers in place.

Extending in an axial direction from the body portion 52 of each packer 28 is a sleeve portion 54 telescopingly received within the well casing 12. Each sleeve includes an outer surface 54A frictionally engageable with the inner wall of the well casing 12 to provide an interference fit between the packer 28 and the well casing. Furthermore, each sleeve 54 includes an inner surface 54B exposed to the chamber 30 and subject to pressure fluctuations within the chamber.

In accordance with the present invention, the outer surface 54A of the sleeve 54 of each packer '28 is provided with a novel rib configuration having several impor tant functions in achieving the results of the invention. The configuration of ribs serves substantially to improve the effectiveness of the seal against pressure, serves to provide in a novel manner a seal against vacuum, and in addition serves to facilitate the insertion and removal of the unit 10 from the well casing 12.

Considering first a situation wherein a pressure condition exists within the chamber 30, an initial seal against pressure is provided by the friction fit of the packers 28 against the well casing 12. This initial seal provides an effective seal against relatively low pressure within the chamber 30. Upon an increase in pressure, the sleeve 54 of the packers 28 are expanded by the pressure force outwardly against the well casing 12 to provide a seal which is pressure energized in that the sealing force increases with increasing pressure. The use of individual ribs on the outer surface 54A concentrates the sealing force over relatively small areas and increases the effectiveness of the seal. The use of individual ribs also permits the surface 54A to conform to irregularities in the wall surface of the well casing. In addition, the inner surface of each sleeve is somewhat tapered and is provided with a highly flexible terminal lip 55 easily biased by pressure within the chamber 30 into intimate contact with the well casing.

The packers 28 also provide an effective initial seal and pressure energized seal against a vacuum or suction condition within the chamber 30. The initial seal results from the interference fit between the packers 28 and the Well casing 12. Upon an increase in vacuum, the novel configuration of ribs serves to provide a pressure energized seal which increases in effectiveness with increasing vacuum.

More specifically, and having reference particularly to FIGS. 3 and 4, the outer surface 54A of the sleeve 54 includes a first group of ribs 56 which are relatively thick and have somewhat rounded ends. Due to their shape, the

ribs 56 are relatively rigid and are not easily flexed in an axial direction. The surface 54A is also provided with an additional group of ribs 58 which are substantially thinner than the ribs 56 and which are tapered or pointed in shape. Due to their shape, the ribs 58 can be flexed relatively easily in an axial direction. The ribs 58 are disposed between pairs of the ribs 56.

Although illustrated only in section, it should be understood that the ribs 56 and 58 are continuous and extend completely around the outer surface 54A of the sleeves 54. In FIG. 3 the ribs 56 and 58- are illustrated in their relaxed condition prior to insertion of the packers 28 into the well casing. It can be seen that the ribs 56 have a maximum outer diameter only slightly greater than the inside diameter of the well casing 12 (indicated by a broken line in FIG. 3). Conversely, the ribs 58 have a maximum outside diameter substantially in excess of the inside diameter of the well casing 12.

As illustrated in FIG. 4, when the chamber 30 is subjected to a suction or a vacuum condition, the relatively thin and flexible ribs 58 are able to be moved under the effect of the pressure differential existing across the ribs in an axial direction. Thus each rib 58 is wedged by this pressure differential into sealing relation between the adjacent rib 56 and the inner wall of the well casing 12. The degree to which the rib 58 is wedged depends upon the pressure differential to which it is subjected, so that the sealing accomplished by the wedging of the rib 58 is pressure energized.

The number and size of the ribs 56 and 58 as well as the degree of interference between the ribs and the well casing 12 are preferably determined in order to facilitate insertion and removal of the unit 10. More specifically, the use of ribs reduces the frictional force required to be overcome when the unit is slid either into or out of the well casing. Preferably, the frictional force is such that it approximately counterbalances the weight of an average length of drop pipe 18 together with the weight of a conventional submersible pump unit. In this manner when the unit 10 is installed in a deep well system the net gravitational force is eliminated or substantially reduced.

Removal of the unit 10 from the casing 12 is also facilitated since there is little or no adhesion between the packers 28 and the casing due to the fact that during operation the packers continually expand and contract with pressure fluctuations. Since there is no metal to metal contact between the casing 12 and the unit 10, noise of the pump is dampened and wear of parts is avoided.

What is claimed and desired to be secured by Letters Patent of the United States is:

1. A distribution unit for use in the well casing of a pitless well installation comprising in combination an elongated tubular conduit, first and second end supports carried on opposite ends of said conduit, and a pair of packers carried respectively by said first and second end supports and sealingly engageable with the well casing to define a pressure isolated chamber within the well casing, each said packer including a body portion of flexible resilient material, and each said end support including a portion encapsulated in the body portion of the corre sponding packer.

2. The distribution unit of claim 1 further comprising means for introducing fluid through said first end support into said conduit, and opening means in said conduit for introducing fluid from said conduit into said chamber.

3. The distribution unit of claim 2, said opening means comprising a large number of relatively small perforations.

4. The distribution unit of claim 1, each said packer including a flexible, resilient sleeve portion having an inner surface exposed to pressure fluctuations within said chamber and an outer surface engageable with the well casing.

5. The distribution unit of claim 4, said outer surface including a plurality of ribs.

6. The distribution unit of claim 5, said ribs including a first group of ribs having a first thickness and a second group of ribs having a second thickness smaller than said first thickness, at least some of the ribs of the first group alternating with at least some of the ribs of the second group.

7. A distribution unit for use within a cylindrical well casing comprising a supporting structure, a pair of packers carried by said supporting structure at spaced regions to define a chamber within said well casing, and means for introducing fluid into said chamber, each said packer including a generally cylindrical sleeve member telescoped within said well casing and having an outer surface of substantial axial extent engageable with the Well casing and an inner surface aligned with said outer surface and freely exposed to pressure fluctuations within said chamber, said sleeve being formed of flexible resilient material permitting said sleeve to expand into sealing engagement against the well casing in response to pressure within said chamber, said outer surface of said sleeve including at least a pair of axially spaced continuous ribs.

8. A distribution unit for use within a cylindrical well casing comprising a supporting structure, a pair of packers carried by said supporting structure at spaced regions to define a chamber within said well casing, and means for introducing fiuid into said chamber, each said packer including a generally cylindrical sleeve member telescoped within said well casing and having an outer surface engageable with the well casing and an inner surface exposed to pressure fluctuations within said chamber, said sleeve being formed of flexible resilient material permitting said sleeve to expand into sealing engagement against the Well casing in response to pressure within said chamber, said outer surface of said sleeve including at least a pair of axially spaced continuous ribs, a first of said ribs located closest to said chamber having a first thickness and being axially rigid, and a second of said ribs adjacent said first rib opposite said chamber being axially flexible and having a second thickness smaller than said first thickness.

9. The unit of claim 8, said first rib having a rounded end and said second rib having a tapered, pointed end.

10. The unit of claim 9, said second rib having a larger maximum diameter than said first rib.

References Cited UNITED STATES PATENTS JAMES A. LEPPINK,

US. Cl. X.R.

Primary Examiner 

